Add qa test for local listings API
Add qa test for local listings API

Fresh node (no listing posted) should return empty list of listings while
after POST one-element list should be returned.

jackkleeman/openbazaar-go,OpenBazaar/openbazaar-go,cpacia/openbazaar-go,gubatron/openbazaar-go,hoffmabc/openbazaar-go,yurizhykin/openbazaar-go,hoffmabc/openbazaar-go,gubatron/openbazaar-go,hoffmabc/openbazaar-go,cpacia/openbazaar-go,yurizhykin/openbazaar-go,JustinDrake/openbazaar-go,jackkleeman/openbazaar-go,yurizhykin/openbazaar-go,duomarket/openbazaar-test-nodes,cpacia/openbazaar-go,duomarket/openbazaar-test-nodes,gubatron/openbazaar-go,duomarket/openbazaar-test-nodes,JustinDrake/openbazaar-go,OpenBazaar/openbazaar-go,JustinDrake/openbazaar-go,OpenBazaar/openbazaar-go,jackkleeman/openbazaar-go